Control of Stefan Problems by Means of Linear-Quadratic Defect Minimization.
Controllability of partial differential equations on graphs
We study boundary control problems for the wave, heat, and Schrödinger equations on a finite graph. We suppose that the graph is a tree (i.e., it does not contain cycles), and on each edge an equation is defined. The control is acting through the Dirichlet condition applied to all or all but one boundary vertices. Exact controllability in L₂-classes of controls is proved and sharp estimates of the time of controllability are obtained for the wave equation. Null controllability for the heat equation...
Controllability properties for the one-dimensional Heat equation under multiplicative or nonnegative additive controls with local mobile support
We discuss several new results on nonnegative approximate controllability for the one-dimensional Heat equation governed by either multiplicative or nonnegative additive control, acting within a proper subset of the space domain at every moment of time. Our methods allow us to link these two types of controls to some extend. The main results include approximate controllability properties both for the static and mobile control supports.
Converegence of a Finite Difference Method for the Heat Equation - Interpolation Technique
Convex domains and unique continuation at the boundary.
We show that a harmonic function which vanishes continuously on an open set of the boundary of a convex domain cannot have a normal derivative which vanishes on a subset of positive surface measure. We also prove a similar result for caloric functions vanishing on the lateral boundary of a convex cylinder.
Convexity and Absolute Continuity of the Laplace-Beltrami Operator.
Convexity and uniqueness in a free boundary problem arising in combustion theory.
We consider solutions to a free boundary problem for the heat equation, describing the propagation of flames. Suppose there is a bounded domain Ω ⊂ QT = Rn x (0,T) for some T > 0 and a function u > 0 in Ω such thatut = Δu, in Ω,u = 0 and |∇u| = 1, on Γ := ∂Ω ∩ QT,u(·,0) = u0, on Ω0,where Ω0 is a given domain in Rn and u0 is a positive and continuous function in Ω0, vanishing on ∂Ω0. If Ω0 is convex and u0 is concave in Ω0, then we show that (u,Ω) is unique and the time sections...
Couplage des équations de Navier-Stokes et de la chaleur : le modèle et son approximation par éléments finis
Damped wave equations and the heat equation
Derivation of a homogenized two-temperature model from the heat equation
This work studies the heat equation in a two-phase material with spherical inclusions. Under some appropriate scaling on the size, volume fraction and heat capacity of the inclusions, we derive a coupled system of partial differential equations governing the evolution of the temperature of each phase at a macroscopic level of description. The coupling terms describing the exchange of heat between the phases are obtained by using homogenization techniques originating from [D. Cioranescu, F. Murat,...
Derivation of high-order spectral methods for time-dependent PDE using modified moments.
Determination of conductivity in a heat equation.
Determination of the source/sink term in a heat equation.
Die Jacobigruppe und die Wärmeleitungsgleichung.
Die Wärmeleitung auf dem Kreis und Thetafunktionen.
Difference schemes with nonlocal boundary conditions.
Distributions of truncations of the heat kernel on the complex projective space
Let be a Brownian motion valued in the complex projective space . Using unitary spherical harmonics of homogeneous degree zero, we derive the densities of and of , and express them through Jacobi polynomials in the simplices of and respectively. More generally, the distribution of may be derived using the decomposition of the unitary spherical harmonics under the action of the unitary group yet computations become tedious. We also revisit the approach initiated in [13] and based on...
Efficient preconditioning for sequences of parametric complex symmetric linear systems.
Ein Gewisses Randproblem aus der Theorie der Wärmeleitfähigkeit
Elementary proofs of some basic subtemperature theorems
We present simple elementary proofs of several theorems about temperatures and subtemperatures. Most of these are concerned with mean values over heat spheres, heat balls, and modified heat balls, with applications to proving Harnack theorems and the monotone approximation of subtemperatures by smooth subtemperatures.